The present invention relates to a rotary compressor that includes a driving element and a rotary compression element inside a sealed container.
Both currently and in the past, a vertical rotary compressor has a configuration shown in FIG. 6, where a driving element 114 is disposed at an upper space inside a vertical cylindrical sealed container 112, and a rotary compression element 118 including a first rotary compression element 132 and a second rotary compression element 134 driven by a rotary shaft 116 of the driving element 114 is disposed below the driving element 114. The rotary compressor 110 is a so-called internal high-pressure-type multi-stage compressing compressor in which a refrigerant gas is compressed by the first rotary compression element 132, is further compressed by the second rotary compression element 134, and then is discharged into the sealed container 112.
The sealed container 112 includes a container body 112A which accommodates the driving element 114 and the rotary compression element 118, and a substantially bowl-shaped end cap 112B (a cover body) which blocks an upper opening of the container body 112A, where the bottom portion thereof is formed as a sump 119. A terminal 120 is attached to the upper surface of the end cap 112B to supply power to the driving element 114.
The driving element 114 includes a stator 122 and a rotor 124 which is inserted into the stator 122 with a slight gap therebetween, and the rotor 124 is fixed to the rotary shaft 116 that extends in the vertical direction along the center of the sealed container 112.
The rotary compression element 118 has a structure in which the first and second rotary compression elements are disposed with an intermediate partition plate 136 interposed therebetween, the first rotary compression element 132 (first stage) is disposed at the opposite side of the driving element 114, and the second rotary compression element 134 (second stage) is disposed at the side of the driving element 114 inside the sealed container 112.
Then, a first support member 151 (a lower support member) serving as a support member is provided to block one (lower) opening of a first cylinder 141 (a lower cylinder) constituting the first rotary compression element 132, and includes a bearing 151A of the rotary shaft 116. A discharge muffling chamber 157 is formed in a manner such that the (lower) surface of the first support member 151 on the opposite side of the first cylinder 141 is recessed, and the recessed portion is blocked by a first cover 159 (a lower cover).
Further, a second support member 152 (an upper support member) is formed to block an upper opening of a second cylinder 142 constituting the second rotary compression element 134, and includes a bearing 152A of the rotary shaft 116. A discharge muffling chamber 158 is formed in a manner such that the (upper) surface of the second support member 152 on the opposite side of the second cylinder 142 is recessed, and the recessed portion is blocked by a second cover 160 (an upper cover). The second cover 160 is provided with a discharge hole 165 which allows the discharge muffling chamber 158 and the interior of the sealed container 112 to communicate with each other.
On the other hand, in the side surface of the container body 112A of the sealed container 112, sleeves 193 and 195 are respectively fixed to a position corresponding to the upper side of the driving element 114 of the first cylinder 141 and a position corresponding to a suction side of the first cylinder 141. One end of a refrigerant introduction pipe 194 is connected to the interior of the sleeve 193 to introduce a refrigerant gas into the first cylinder 141. Further, the refrigerant discharge pipe 196 is inserted and connected to the interior of the sleeve 195, the end portion of the refrigerant discharge pipe 196 is opened to the interior of the sealed container 112, and the refrigerant discharge pipe communicates with the interior of the sealed container 112.
Then, the refrigerant gas is suctioned from a suction port (not shown) to a low pressure side of the first rotary compression element 132, is subjected to a first-stage compression to receive a medium pressure, and is discharged to the discharge muffling chamber 157 from the high pressure side of the first rotary compression element 132. The refrigerant gas having a medium pressure and discharged to the discharge muffling chamber 157 is suctioned to the low pressure side of the second rotary compression element 134, is subjected to a second-stage compression to become a high-temperature and high-pressure refrigerant gas, enters the discharge muffling chamber 158, and is discharged upward from the discharge hole 165 of the second cover 160. The discharged high-temperature and high-pressure refrigerant gas moves to the upper side of the sealed container 112 via a gap in the driving element 114, and is discharged from the refrigerant discharge pipe 196 connected to the upper side of the sealed container 112 to the outside of the rotary compressor 110.
However, in the existing internal high-pressure-type multi-stage compressing rotary compressor 110, oil is dissolved in the refrigerant gas compressed by the second rotary compression element 134 and discharged from the discharge hole 165. The refrigerant gas with oil dissolved therein flies in the rotation direction of the rotary shaft 116 due to the inertia accompanying the rotation of the driving element 114. The discharged refrigerant gas and oil move upward via a gap between the stator 122 and the rotor 124, the interior of the rotor 124, or a gap between the sealed container 112 and the stator 122, and arrive at the upper side of the driving element 114. Then, the refrigerant gas and oil collide with the inner surface of the end cap so that some of it flies or adhere thereto.
Then, the oil inside the refrigerant is separated through the passage or the collision, the separated oil adheres to the inner surface of the sealed container 112, and the oil flows down to the lower sump 119 along the inner surface of the sealed container. However, a part of the oil moves in a floating state in the space above the driving element 114, and flows from the opening into the refrigerant discharge pipe 196, so that the oil exits the sealed container 112. In this case, the amount of refrigerant moving upward through the driving element 114 is smallest at the center of the sealed container 112 with the rotary shaft 116. For this reason, in the past, as shown in FIG. 7, the refrigerant discharge pipe 196 was opened in the horizontal direction (opened in the direction perpendicular to the sealed container 112), but the amount of oil exiting the sealed container 112 was not small.
Then, when the oil exits the sealed container during the refrigerating cycle, the amount of the oil inside the sealed container 112 is not sufficient, so that the circulation of the refrigerant is degraded. In particular, in recent years, in order to improve the performance of the rotary compressor 110, the refrigerant discharge pipe 196 has been set to have a larger diameter than that of the related art. Accordingly, the oil may easily exit the sealed container 112 through the refrigerant discharge pipe 196.
Therefore, there is disclosed a structure in which an annular shielding plate is provided at an upper portion of a stator of a motor inside a sealed container, a refrigerant discharge pipe is formed in a bent shape to separate oil dissolved in a refrigerant gas from the interior of the sealed container, and only the refrigerant gas is discharged from the sealed container, so that the amount of the oil exiting the refrigerant discharge pipe is reduced (for example, refer to Japanese Patent Application Laid-Open No. 2006-336481 (Patent Document 1)).
However, when the structure shown in Patent Document 1 is adopted in order to reduce a problem in which the oil exits the refrigerant discharge pipe, a problem arises in that the structure becomes complicated.
Therefore, when only the front end of the refrigerant discharge pipe is subjected to drawing in order to be thinned, the problem of the oil exiting the refrigerant discharge pipe may be reduced. However, a problem arises in that a processing cost increases due to the drawing performed on the front end of the refrigerant discharge pipe.